CMF / CRF Details

CMF ID: 4887

Replace Night-Time Flash with Steady Operation


Prior Condition:  Traffic signals were operating in the late night flash (LNF) mode from late night to early morning hours.

Category: Intersection traffic control

Study: Safety Evaluation of Discontinuing Late Night Flash Operations at Signalized Intersections, Lan and Srinivasan, 2013

Star Quality Rating:4 Stars  [View score details]
Rating Points Total:120
Crash Modification Factor (CMF)
Adjusted Standard Error:
Unadjusted Standard Error:0.06
Crash Reduction Factor (CRF)
Value:48  (This value indicates a decrease in crashes)
Adjusted Standard Error:
Unadjusted Standard Error:6
Crash Type:All
Crash Severity:All
Roadway Types:All
Street Type:
Minimum Number of Lanes:
Maximum Number of Lanes:
Number of Lanes Direction:
Number of Lanes Comment:
Crash Weather:Not specified
Road Division Type:All
Minimum Speed Limit:
Maximum Speed Limit:
Speed Unit:
Speed Limit Comment:
Area Type:All
Traffic Volume:
Average Traffic Volume:
Time of Day:Night
If countermeasure is intersection-based
Intersection Type:Not specified
Intersection Geometry:3-leg,4-leg
Traffic Control:Signalized
Major Road Traffic Volume:Minimum of 2550 to Maximum of 59000 Annual Average Daily Traffic (AADT)
Minor Road Traffic Volume:Minimum of 1000 to Maximum of 23333 Annual Average Daily Traffic (AADT)
Average Major Road Volume :21837 Annual Average Daily Traffic (AADT)
Average Minor Road Volume :7955 Annual Average Daily Traffic (AADT)
Development Details
Date Range of Data Used:2000 to 2007
Type of Methodology Used:Before/after using empirical Bayes or full Bayes
Sample Size (crashes):482 crashes before, 86 crashes after
Other Details
Included in Highway Safety Manual?No
Date Added to Clearinghouse:Aug 01, 2013
Comments:The study reports CRFs using 3 methods (univariate EB, univariate FB, and multivariate FB). The authors concluded that the multivariate FB gives the most accurate results. The summary statistics are approximations because 4 sites were removed from the final analysis and the final summary statistics were not provided.